With at least 16Gbs of OS RAM (Linux & Windows) and a consistent 566Mbps broadband connection speed, for the most part one browser seems as fast as the other. Though if you employ certain privacy measures, such as using "Tor" in the Brave browser, it's bound to run slower given what it must do to accomplish such a degree of anonymity.
On the other hand, using Google means allowing them to rummage through your entire computer just to sell your browsing habits to the rest of the planet. Same as Microsoft Edge using the same browser engine, but with a little more polished appearance.
Firefox continues to enhance privacy features and still maintains a sidebar in which you can refer to your most immediate browsing history. (I purge it routinely along with the browser cache upon exit.) I've had Firefox as a default browser ever since it replaced Mozilla's Netscape. And of course I keep any and all of Firefox's telemetry (feedback) functions turned off. Can't say I always keep many browser tabs open at the same time. Maybe three-to-four tops. Though I always purge my browser cache on exit.